Just had a thought. I could try the game under Wine on a different model of MacBook with a different video card. Using the same OS, Wine and X versions should keep most things equal, providing some evidence as to whether the problem is at the level of the game software, Wine, X, video divers or OS. I'm already fairly confident that the game, Wine and X are ok since they work under Parallels. Keeping the OS constant but changing the video card should be the next step.